Seat cushion



Oc zt. 18, 1949. E. R. HATHAWAY SEAT CUS'HION 2 Sheets-Sheet 1 Filed Feb. 8, 1945 I INVENTOR. Flt 4rd Z flaiiawagy.

Oct. 18, 1949. E. R. HATHAWAY 2,485,443

SEAT CUSHION Filed Feb. 8, 1945 2 Sheets-Sheet 2 INVENTOR.

Patented Oct. 18, 1949 UNITED STATES PATENT OFFICE SEAT CUSHION Edward R. Hathaway, Detroit, Mich., assignor to Briggs Manufacturing Company, Detroit, Mich., a corporation of Michigan Application February 8, 1945, Serial No. 576,743

3 Claims. 1 This invention relates to springs generally useful in the fabrication of the upholstered seat cushions and backs of seat structures, the invention relating particularly to improvements in the construction of so-called fiat type wire springs of sinuous or zig-zag formation.

An object of the invention is to provide a spring structure made up of a series of parallel rows of spring members each having an improved zig-zag formation adapted to have a greater effective range of deflection under load.

A further object of the invention is to provide a spring of generally zig-zag construction formed from a length of wire bent into a series of alternate loops in such manner as to improve the resiliency of the structure and provide progressively increasing resistance to load over a wider deflection range than possible with flat-type sinuous springs heretofore used.

Other objects of this invention will appear in the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

Fig. 1 is a plan view of a spring structure embodying spring members constructed in accordance with the present invention.

Fig. 2 is a section taken substantially through lines 22 of Fig. 1 looking in the direction of the arrows.

' alternating loops provides in effect two rows of Fig. 3 is an enlarged fragmentary view of a porstruction and arrangement of parts illustrated in the accompanying drawings, since the invention is ends by end members H. Extending transversely between and spanning the side frame members It are a series of individual spring members l2 spaced equal distances apart and arranged in parallelism. Each spring member I2 is formed from a single length of steel wire of suitable gage which is bent into a zig-zag formation having alternate loops l3 and Hi all lying in the same plane when the spring is in fiat condition before installation in the frame. Thesprings before assembly are pre-set so that when mounted in the frame they assume under tension an outwardly, or upwardly as the case may be, bowed or curved position as shown in Fig. 2. The ends of each spring member maybe anchored in any suitable manner such as by inserting the ends into channels formed by the members It; the sides of which are crimped together to clamp the ends of the spring tightly inposition.

The alternating loops l3 and M of each spring member are each preferably formed into substantially identical general elliptical shape and are nested together so that substantial end areas of each loop overlap or lie opposite to equivalent areas of two adjacent opposed loops. Thus, as clearly illustrated in Fig. 1, the formation of the loops in the longitudinal direction of the spring.

As shown particularly in Fig. 3 each loop 13 and M' is formed and arranged so that its length measured longitudinally of the spring is materially greater than its width measured in a transverse direction. Thus, the length of the loop capable of other embodiments and of being practiced or carried out in various ways. Also it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

In the drawings there is illustrated, by way of example, one embodiment of the invention adapted to be utilized in the fabrication of an upholstered seat or back structure. Any suitable supporting frame or mounting ma be employed in the spring assembly such as a rectangular metal frame illustrated in the drawings comprising spaced side members It connected at their measured through the major axis thereof is represented by the distance a: and the width of the loop measured through the minor axis thereof is represented by the distance y. In the present embodiment herein selected for the purposes of illustration, the distance a: is approximately twice the distance 11 the latter corresponding to approximately one-half the entire Width of the spring member. With this construction the length of each loop corresponds approximaely to the width of the spring member. The adjacent loops I3 or l4 are preferably arranged in close relationship with the distance 10 between each adjacent pair being much less than the length of the loop, such as approximately one-fifth the distance :0. Furhermore, it will be noted that this construction provides a very closely nested arrangement of the alternating loops in which the centers thereof lie on a zig-zag line as indicated by the dotted line a in Fig. 3. It will be understood that the shape and size of the loops as well as the dimensional scope of the invention without departing from the spirit thereof.

With the alternating loops l3 and I4 arranged in nested relation with their major axes extending longitudinally of the spring instead of transversely as heretofore it has been found by comparative tests that the present spring will sustain much greater loads without collapse than flat-type sinuous springs heretofore used. In

Fig. 4 there is illustrated graphically the deflection rate of a spring constructed in accordance with the present invention as compared with a conventional spring of sinuous construction having a deflection rate illustrated graphically in Fig. 5. This conventional spring had elongate transversely extending relatively narrow U- shaped loops with substantially parallel sides, this construction being common in the prior art. The comparative tests were made with springs formed with the same gage steel wire and Were in all respects conducted so that reliable comparisons were reached. In each instance the spring member tested was mounted in bowed or arched manner, as illustrated in Fig. 2, the crown of the spring at the highest point being two inches above a horizontal plane extending through the ends of the spring. In the graph illustrated in Fig. 4, depicting the tests conducted on a spring member substantially as illustrated in the drawings, the deflection rate is shown by the curve or graph line 15 extending through a series of points determined by measuring in inches successive increments of downward deflection of the spring produced by successive loads, measured in pounds, placed on the spring. It will be noted from this graph that the spring deflection progressively increased as the load increased, and that the spring resistance had a magnitude of twenty-seven pounds when a deflection of four inches was reached. Referring to the graph illustrated in Fig. 5, depicting the tests made with a conventional fiat spring, the maximum effective resistance of the spring Was reached at a deflection of two and three-fourths inches under a load of eighteen pounds, as shown by the curve or graph line 16. From this point the spring started to collapse and the effective resistance of the spring with a four inch deflection was but slightly over eleven pounds.

Thus, it will be seen that the present improved spring possesses a considerably greater effective deflection range than flat springs of conventional type and is capable not only of sustaining progressively increasing loads throughout this range but materially greater loads than heretofore possible with conventional flat-type sinuous springs. 5

I claim:

1. In a seat structure or the like having a frame, a plurality of flat-type spring members normally bowed upwardly from a substantially horizontal plane and being arranged on said frame in curvilinear alignment, each of said spring members comprising a length of wire formed to provide alternating reversely bent loops extending transversely of the spring member, the distance between the closed ends of each loop measured 1ongitudinally of the spring member being greater than the width of the loop measured transversely from the outer edge of the loop to an imaginary line running lengthwise of the spring member at the middle thereof from side to side.

2. In a seat structure or the like having a frame, a plurality of flat-type spring members normally bowed upwardly from a substantially horizontal plane and. being arranged on said frame in curvilinear alignment, each of said spring members comprising a length of wire formed to provide alternating reversely bent loops extending transversely of the spring member, the distance between the closed ends of each loop measured longitudinally of the spring member being approximately as great as the width of the spring member.

3. In a seat structure or the like having a frame, a plurality of flat-type spring members normally bowed upwardly from asubstantially horizontally plane and being arranged on said frame in curvilinear alignment, each of said spring members comprising a length of wire formed to provide alternating reversely bent elliptically shaped loops extending transversely of the spring member, the major axis of each loop extending longitudinally of the spring member and approximating the width of the latter, and the width of the opening between the ends of adjacent loops being less than half of the length of said major axis.

" EDWARD R. HATHAWAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 751,147 Caspary Feb. 2, 1904 890,559 Dodd June 9, 1908 2,123,888 Freund July 19, 1938 2,217,893 Dunajefi? Oct. 15, 1940 FOREIGN PATENTS Number Country Date 16,814 Great Britain 1909 

